著者

李 松杰 秋山 英二 篠原 正 松岡 和巳 押川 渡

出版者

一般社団法人 日本鉄鋼協会

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.99, no.11, pp.651-658, 2013 (Released:2013-10-31)

参考文献数

42

被引用文献数

5

---

Electrochemical hydrogen permeation tests of pure Fe sheets rusted by cyclic corrosion test (CCT) and atmospheric exposure were carried out under controlled temperature and humidity to investigate the influence of atmospheric corrosion on the hydrogen entry behavior. The hydrogen entry into the Fe specimens rusted by CCT increased under wet condition, and the hydrogen entry was increased with the CCT cycle number. During drying process after the wetting, hydrogen entry was further enhanced and a peak of hydrogen current was observed. The peak hydrogen permeation current tended to increase with the growth of rust layer, and the peak value of the hydrogen permeation current became remarkably higher than that at the highest humidity when the rust layer was relatively thick. Similar enhancement of hydrogen entry into an outdoor-exposed specimen was also observed during drying. Drying process after CCT resulted in an increase in hydrogen content of 5 mm-thick steel specimens measured by means of thermal desorption analysis, indicating the enhancement of hydrogen entry during drying process and showing a good agreement with the electrochemical hydrogen permeation test results. It is required to take into consideration the enhanced hydrogen entry to estimate concentration of hydrogen from the environment.

著者

大森 惇志 秋山 英二 阿部 博志 端 邦樹 佐藤 智徳 加治 芳行 井上 博之 田口 光正 清藤 一 多田 英司 鈴木 俊一

出版者

公益社団法人 腐食防食学会

雑誌

Zairyo-to-Kankyo (ISSN:09170480)

巻号頁・発行日

vol.69, no.4, pp.107-111, 2020-04-10 (Released:2020-10-01)

参考文献数

14

被引用文献数

1 1

---

ガンマ線照射による水のラジオリシスで生成する酸化剤が炭素鋼の気相中の腐食に及ぼす効果を評価するために,オゾンをモデル酸化剤として用いて50℃の湿度制御下に導入し,ACMセンサを用いた腐食モニタリングを行なった.ACM電流はオゾンの濃度に伴って高くなったことから,オゾンによる腐食促進の効果が示された.これはオゾンの還元反応あるいは水への溶解反応が早く,カソード反応を促進したためと考えられる.

著者

小林 直弘 小山 元道 小林 憲司 北條 智彦 秋山 英二

出版者

公益社団法人 日本金属学会

雑誌

日本金属学会誌 (ISSN:00214876)

巻号頁・発行日

vol.85, no.2, pp.49-58, 2021-02-01 (Released:2021-01-25)

参考文献数

35

被引用文献数

6 5

---

The grain size effects on the hydrogen embrittlement susceptibility of pure Ni and Ni-20Cr alloy were investigated. The hydrogen embrittlement susceptibility was evaluated by tensile testing under electrochemical hydrogen charging. Relative elongation, defined as the elongation under hydrogen charging divided by elongation in air, increased with increasing grain size in pure Ni (the grain size was in the range of 11-22 µm). In contrast, the relative elongation of Ni-20Cr alloy increased with decreasing grain size from 13 to 1.8 µm. Correspondingly, intergranular fracture was suppressed by grain coarsening in pure Ni and grain refinement in the Ni-20Cr alloy. In addition, the intergranular fracture surface in pure Ni showed curved slip lines, and in the Ni-20Cr alloy showed straight line marks. These fractographic features imply that the mechanisms of the hydrogen-assisted intergranular crack growth were different in pure Ni and Ni-20Cr alloy and this can be attributed to the difference in stacking fault energy.

著者

秋山 英二

出版者

公益社団法人 日本金属学会

雑誌

まてりあ (ISSN:13402625)

巻号頁・発行日

vol.56, no.3, pp.230-233, 2017 (Released:2017-03-01)

参考文献数

64

被引用文献数

1 3

著者

秋山 英二 李 松杰 片山 英樹 張 波萍 趙 楷 押川 渡

出版者

一般社団法人 日本鉄鋼協会

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.103, no.2, pp.93-100, 2017

---

<p>Electrochemical hydrogen permeation tests were carried out under controlled temperature and humidity using pure Fe sheet specimens outdoor-exposed at Beijing and Chongqing, China and Okinawa, Japan in order to understand the effect of environmental factors on hydrogen uptake behavior. The maximum hydrogen permeation current densities of the exposed specimens were in the order of Beijing > Chongqing >> Okinawa, while the order of the degree of corrosion of the specimens was Okinawa > Chongqing >> Beijing. X-ray fluorescence analysis showed that the surface concentrations of sulfur on the Beijing- and Chongqing-exposed specimens were higher than that of the Okinawa-exposed specimens, whereas chlorine concentrations of the Beijing and Okinawa-exposed specimens were higher than that of the Chongqing-exposed specimen. Nitrate concentrations of Beijing- and Chongqing-exposed specimens evaluated using nitrate test strips were obviously higher than that of the Okinawa-exposed specimens. It is suggested that air pollutants such as SO₂ and NO₂ and particulate matters containing inorganic acid ions, likely sulfate and nitrate ions, and possibly organic acids contribute to acidification of rust layer leading to the enhanced hydrogen entry.</p>

著者

小山 元道 秋山 英二 津﨑 兼彰

出版者

一般社団法人 日本鉄鋼協会

雑誌

鉄と鋼 (ISSN:00211575)

巻号頁・発行日

vol.100, no.9, pp.1132-1139, 2014 (Released:2014-08-31)

参考文献数

36

被引用文献数

4

---

Al effects on strain aging and resistance against hydrogen embrittlement were examined in Fe-18Mn-0.6C-based twinning-induced plasticity steels deformed at different strain rates. The Fe-18Mn-0.6C steel showed hydrogen-induced fracture when it had been pre-deformed at a strain rate of 1.7×10–6 s–1. The hydrogen-induced fracture was suppressed by increasing strain rate and increasing Al content. From the viewpoint of material strengthening by strain aging, we found two important factors improving the resistance to the hydrogen embrittlement; (1) suppression of dynamic strain aging by increasing strain rate and Al content, and (2) suppression of static strain aging under loading by the Al addition.